Mutability & Immutability, What’s the Difference?

Mutable Objects: The Malleable Entities

Mutable objects, as the name suggests, are flexible. They can be altered or 'mutated' after they've been initialized. This means that their internal state or data can change over time, often in response to program actions or operations.

For example, consider a list in Python. You can add, remove, or modify its elements after its creation, making it a classic example of a mutable object.

Advantages:

• Flexibility: Mutable objects can be adjusted on-the-fly, making them adaptable to dynamic data or changing requirements.
• In-Place Modifications: Since you can change the content directly, there's no need to create a new object every time a change is needed. This can be memory-efficient for large data structures.

Drawbacks:

• Thread Safety: Mutable objects can be tricky in multi-threaded environments. Simultaneous modifications by different threads can lead to unpredictable behaviors or data corruption.
• Predictability: Continuous changes to an object can make the flow of data harder to trace and debug.

Immutable Objects: The Constants in Chaos

Contrastingly, immutable objects are set in stone. Once they're created, their state remains unchanged. Any operation that seems to alter them actually creates a new object with the desired changes, leaving the original untouched.

Take the example of strings in many programming languages. When you "modify" a string, you're often creating a new one while the original remains unaltered.

Advantages:

• Thread Safety: Since the state of an immutable object never changes, there's no risk of data corruption from simultaneous modifications. This makes them inherently safe in concurrent or parallel processing scenarios.
• Predictability & Readability: With no unexpected changes, the behavior of immutable objects is easier to understand, making the code more readable.
• Security: Immutable objects can't be tampered with, ensuring data integrity.

Drawbacks:

• Memory Overhead: Every "modification" leads to a new object, which can be memory-intensive for large data structures or frequent changes.

Getting It?

Simply put, a mutable object can have its internal state changed aka 'mutated', whereas an immutable object cannot be changed once created.

Strings are an example of objects that are immutable. They are frequently used in programming to improve readability and runtime efficiency. These objects are also advantageous because they are by nature, thread-safe, easier to understand and reason about, and provide greater security in comparison to mutable objects.

Ultimately, whether an object is mutable or immutable can greatly influence how it is used and the overall performance of your code.

So, should I use mutability or immutability? Let's dig a little deeper and see what situations are preferable for both.